That's a totally subjective opinion.
Erm, well... not really. You can avoid overlap like the plague, if you settle right in Shakas face and cut him off from further expansion, there WILL be a DoW. I won't go through every possible scenario, but you get my point.
I had tons of games where i had zero (numerical: 0) overlap and still got DoW'd by Deity AIs. Even had the same thing on Immortal recently. My subject oppinion? Okay, your subject oppinion too, i guess.
You have absolutely no backup data about how much overlap matters but downgrade it.
I'm not saying that what you wrote is wrong - i'm just saying that, no matter what you say how bad overlap is for DoW checks, i'll just keep on overlapping. You know, not everyone plays huge maps where you have tons of space to expand into, and when i roll a fractal-alike map on Deity, i'll have to overlap or won't get out more than 2 cities sometimes. Not to mention that i will chose to overlap, even when i don't have to by all means, because it's useful. You know, not everyone plays HoF where a DoW cripples your score and whatever.
After all, Diplo's still the way to go to avoid DoWs on Normal/Normal, and tbh i won't argue with you on "your" gamestyle because, to be perfectly honest, i'm not interested in Marathon or huge. Not - a - single - bit. I'm thankful for that you provided me that information, but avoiding overlap to avoid DoWs is simply not an option in my games, believe it or not. My subject oppionion, yeah well, deal with it.